Field of the Invention
This invention relates to a method (hereinafter referred to as being of the kind specified) of applying a succession of strips of mat to the roof of an underground mine working in a manner such that each successive strip is applied along a previously uncovered zone of the roof bordering the last applied one of the previously applied strips, and with the nearer edges of these two strips in proximate relation to each other. The invention also relates to an apparatus (hereinafter referred to as being of the kind specified) comprising applicator means for applying a strip of flexible roof mat to the roof of a mine working, said strip being drawn off from a store, and transporter means for moving said applicator means in a direction longitudinally along a succession of generally parallel paths to enable successive strips of mat to be applied to the roof along respective parallel adjacent zones.
In my prior U.S. Pat. No. 3,399,927 I have disclosed the laying or applying of mat strips, for example wire mesh, in closely adjacent parallel formation. This mat applying operation follows step by step the coal cutting operation and the newly laid strips of mat are supported at intervals by roof bars of support units. However, it is not always possible to prevent the opening of gaps occurring between adjacent strips of mat and there is then an increased possibility of rocks and a corresponding amount of dust falling through these gaps.
To avoid or reduce exposure of personnel to such rock falls certain improvements were described and claimed in my U.S. Pat. No. 4,099,785 and in particular the location of the stored portion of roof mat strip in a zone already protected by roof supports.
Further, in my U.S. Pat. No. 4,122,682 I have described and claimed the further invention of effecting a mechanical connection between adjacent strips of mat as each new strip is applied to the roof, all of these inventions progressively increasing the safety of mine personnel and the cleanliness of the atmosphere by minimising dust generation arising from roof falls.
If, however, the mat applicator means is mounted on the mining machine, for example on a coal cutting machine, and in particular on a shield plate or cowl which extends part of the way around a coal cutting cylinder, while it is possible in this way to provide immediate support by way of the newly applied mat to the roof areas newly exposed behind the cutting cylinder, the mat applicator means will follow the movements of the cutting cylinder including any lateral deviations which the latter may make transversely of a coal face. In this respect unevenness in the floor of the mine working may cause rails on which the mining machine is mounted to run parallel to the coal face to exhibit differential undulations or changes in level and this causes lateral tilting of the whole mining machine so that the cutter is thereby caused to deviate laterally by way of movement towards and away from the coal face.
One consequence of this is that the lateral deviations are inevitably transmitted to the mat applicator means with the result that what should be proximate edges, one on each of respectively adjacent strips of mat, tend to be overlapped excessively or gaps allowed to exist between them.
Not only are such gaps disadvantageous for the reasons previously stated, but also their existence interferes with the proper operation of the method and apparatus the subject of my U.S. Pat. No. 4,122,682 previously mentioned and wherein the strips are mechanically fastened together.
It is, therefore, the principal aim of the present invention to reduce such gaps and excessive overlap.